AD Amdt-39-10186

[Federal Register Volume 62, Number 211 (Friday, October 31, 1997)]
[Rules and Regulations]
[Pages 58892-58894]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 97-28742]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-ANE-52-AD; Amendment 39-10186; AD 97-22-14]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CF6-50 and -
80C2 Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to General Electric Company (GE) CF6-50 and -80C2 series 
turbofan engines. This action requires removal from service of 
defective high pressure compressor rotor (HPCR) stage 3-9 spools, and 
replacement with serviceable parts. This amendment is prompted by a 
report of an uncontained failure of an HPCR stage 3-9 spool installed 
on a GE model CF6-80C2 turbofan engine. The actions specified in this 
AD are intended to prevent failure of the HPCR stage 3-9 spool, which 
can result in an uncontained engine failure and damage to the aircraft.

DATES: Effective November 17, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 17, 1997.

[[Page 58893]]

    Comments for inclusion in the Rules Docket must be received on or 
before December 30, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 97-ANE-52-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may also be sent 
via the Internet using the following address: ``<a href="/cdn-cgi/l/email-protection#dde4f0bcb9f0d7b8b3bab4b3b8adafb2ad9dbbbcbcf3b9b2a9f3bab2ab">9-ad-
<span class="__cf_email__" data-cfemail="dbbeb5bcb2b5beaba9b4ab9bbdbabaf5bfb4aff5bcb4ad">[email&#160;protected]</span></a>''. Comments sent via the Internet must contain 
the docket number in the subject line.
    The service information referenced in this AD may be obtained from 
General Electric Company Technical Services, Attention: Leader for 
distribution/microfilm, 10525 Chester Road, Cincinnati, OH 45215; 
telephone (513) 672-8400 Ext. 114, fax (513) 672-8422. This information 
may be examined at the FAA, New England Region, Office of the Assistant 
Chief Counsel, 12 New England Executive Park, Burlington, MA; or at the 
Office of the Federal Register, 800 North Capitol Street, NW., suite 
700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: William Ricci, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7142, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: The Federal Aviation Administration (FAA) 
has received a report of an uncontained failure of a high pressure 
compressor rotor (HPCR) stage 3-9 spool installed on a GE model CF6-
80C2 turbofan engine. The investigation revealed that a crack initiated 
in the HPCR stage 3-9 spool and propagated in low cycle fatigue to 
rapid fracture and disk rupture. The crack initiated from an oxygen 
stabilized alpha region located in the area of the stage 3 dovetail 
blade slot and propagated radially inward to the disk bore. The FAA has 
determined that HPCR stage 3-9 spools produced from the same melt of 
material may also be affected. The investigation is continuing and 
pending the results of the investigation the requirements of this AD 
may be changed. This condition, if not corrected, could result in 
failure of the HPCR stage 3-9 spool, which can result in an uncontained 
engine failure and damage to the aircraft.
    The FAA has reviewed and approved the technical contents of GE CF6-
50 Service Bulletin (SB) 72-A1139, dated October 17, 1997, and GE CF6-
80C2 SB 72-A906, dated October 17, 1997, that describe procedures for 
removal from service of defective HPCR 3-9 spools, and replacement with 
serviceable parts.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of the same type design, this AD is 
being issued to prevent failure of the HPCR 3-9 spool. This AD 
requires, within 30 days after the effective date of this AD, removal 
from service of defective HPCR 3-9 spools, and replacement with 
serviceable parts. This calendar end-date was determined based upon 
risk analysis. The actions are required to be accomplished in 
accordance with the SBs described previously.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications should identify the Rules Docket number and be submitted 
in triplicate to the address specified under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available, both before and after the closing date for comments, in the 
Rules Docket for examination by interested persons. A report that 
summarizes each FAA-public contact concerned with the substance of this 
AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 97-ANE-52-AD.'' The postcard will be date stamped and 
returned to the commenter.
    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a ``significant regulatory action'' 
under Executive Order 12866. It has been determined further that this 
action involves an emergency regulation under DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979). If it is determined 
that this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, may 
be obtained from the Rules Docket at the location provided under the 
caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

97-22-14  General Electric Company: Amendment 39-10186. Docket 97-
ANE-52-AD.

    Applicability: General Electric Company (GE) CF6-50 and -80C2 
series turbofan engine, installed on but not limited to Boeing 767 
and 747 series, McDonnell Douglas DC-10 and MD-11, and Airbus 
Industries A300 and A310 series aircraft.

    Note 1: This airworthiness directive (AD) applies to each engine 
identified in the preceding applicability provision, regardless

[[Page 58894]]

of whether it has been modified, altered, or repaired in the area 
subject to the requirements of this AD. For engines that have been 
modified, altered, or repaired so that the performance of the 
requirements of this AD is affected, the owner/operator must request 
approval for an alternative method of compliance in accordance with 
paragraph (b) of this AD. The request should include an assessment 
of the effect of the modification, alteration, or repair on the 
unsafe condition addressed by this AD; and, if the unsafe condition 
has not been eliminated, the request should include specific 
proposed actions to address it.

    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent failure of the high pressure compressor rotor (HPCR) 
3-9 spool, which can result in an uncontained engine failure and 
damage to the aircraft, accomplish the following:
    (a) Within 30 days after the effective date of this AD, remove 
from service HPCR 3-9 spools identified by serial number in the 
applicable service bulletin (SB), and replace with serviceable 
parts, as follows:
    (1) For GE CF6-50 series turbofan engines, remove and replace in 
accordance with GE CF6-50 SB 72-A1139, dated October 17, 1997.
    (2) For GE CF6-80C series turbofan engines, remove and replace 
in accordance with GE CF6-80C2 SB 72-A906, dated October 17, 1997.
    (b) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Engine Certification Office. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, Engine Certification Office.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (c) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the aircraft to a location where 
the requirements of this AD can be accomplished.
    (d) The actions required by this AD shall be done in accordance 
with the following GE SBs:

------------------------------------------------------------------------
            Document No.              Pages              Date           
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CF6-50 SB 72-A1139.................      1-7  Oct. 17, 1997.            
  Total pages: 7.                                                       
CF6-80C2 SB 72-A906................      1-7  Oct. 17, 1997.            
  Total pages: 7.                                                       
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    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from General Electric Company 
Technical Services, Attention: Leader for distribution/microfilm, 
10525 Chester Road, Cincinnati, OH 45215; telephone (513) 672-8400 
Ext. 114, fax (513) 672-8422. Copies may be inspected at the FAA, 
New England Region, Office of the Assistant Chief Counsel, 12 New 
England Executive Park, Burlington, MA; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.
    (e) This amendment becomes effective on November 17, 1997.

    Issued in Burlington, Massachusetts, on October 22, 1997.
James C. Jones,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 97-28742 Filed 10-30-97; 8:45 am]
BILLING CODE 4910-13-U